Our long-term objective is to unravel mechanisms by which endometriosis causes infertility in females within families. The cause of reduced fecundity in endometriosis remains one of the greatest enigmas in reproductive medicine. Evidence supports an association between endometriosis and transgenerational infertility, yet the cause and effect relationship is unknown. This leads to billions of dollars spent annually on health care for symptom-driven, non-curative therapeutic approaches. This project will test the exploratory hypothesis that in utero exposure to endometriosis causes multigenerational reproductive anomalies in the offspring and reprogramming of gene expression in gametes and preimplantation embryos in three generations, which will translate into novel, unforeseen treatments to restore fertility in women with endometriosis. Specific Aim 1: Developmental (in utero) exposure to endometriosis of embryos or the embryo's embryonic germ cells manifests as abnormal litter and offspring characteristics, poor gamete quality and delayed/arrested embryo development in three generations of progeny from Endo vs. Control rats. Specific Aim 2: Subfertility in endometriosis is caused by molecular aberrations in DNA methylation and/or histone modifications of gametes (oocyte/sperm imprinting) and epigenetic DNA modifications and chromatin reorganization in embryos in a sex-specific manner thus altering gene expression pathways critical for gamete function and embryo development in three generations of Endo rats. Deciphering molecular mechanisms by which endometriosis disrupts fertility across multiple generations will facilitate discovery of prime targets for development of revolutionizing clinical interventions addressing the cause or even prevention of subfertility in women with endometriosis. These studies will be the first to determine whether multigenerational transmission causes alterations in embryo gene expression via the female and/or male. The significance to human reproductive health is enormous. These new interventions are paramount to evolve from surgical or chemical obliteration of lesions or repeated unsuccessful attempts at IVF. They also provide an avenue to test safety and efficacy of new paradigm changing clinical interventions and assist rapid translation of knowledge from the bench to the infertility clinic.